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and, in short, forms, as its name implies, a perfect hot-bed for the growth of all those fungi that used to be considered as the causes, but which are only the most usual symptoms, of dry rot. It is a proverb among the people of the dockyard, that a month in the hole is worse for a bit of timber, than ten years in almost any possible situation out of it :-and the government, pestered with the eternal applications of the rol-doctors, have hitherto found their safety-valve in this fungus pit. Mr. Knowles concludes one of his chapters with a distinct statement that no prepared timber, exposed during twelve months to the action of this ordeal, had, unless insulated by some other substance,

entirely resisted the influence of the gas.' (p. 55.) We have ourselves visited this noxious place, and seen an hour and a half elapse, after opening the trap-door, before a candle would burn six inches beneath the surface. Blocks of timber-oak, elm, pine, beech, &c.— prepared with the solution of sublimate, have now, as Mr. Faraday said, and as the printed documents before us prove distinctly, stood the test of the fungus pit, without exhibiting the slightest symptom of decay, during no less a period some of them than five years: and these, instead of being insulated by means of some heterogeneous substance, had been lying on the fungus-spread floor of the dungeon, each with an unmedicated fragment of the very same tree, and of the like bulk, close by its side -every one of which unprepared pieces was found at the opening of the pit in rapid progress to decomposition. The results of various experiments, instituted by Sir Robert Smirke, the eminent architect, with a view to his own professional business, were in like manner detailed, and his evidence as to the power of timbers prepared in this method to resist the action of dropping eaves, &c. during a course of time sufficient to bring utter decay upon unprepared ones similarly exposed, was not less satisfactory than the upshot of the long trials at Woolwich.

The primâ facie efficacy of the application was illustrated, as some thought even more remarkably, by the exhibition of pieces of canvass, and even of delicate calico cloth, which had been placed during from two to three months on the floor of the fungus pit.

The prepared pieces came out entirely sound, while, of the unmedicated counterparts, there remained nothing but a few mildewed strings that fell to pieces at the touch.

The lecturer stated, on the authority of Mr. Kyan, that cubes of oak, Memel pine, &c., containing each 216 cubical inches, imbibe, notwithstanding the difference of their structures, as nearly as can be measured, the very same quantity of the solution—about five ounces each; a quantity so small, that the expense of the operation is a mere trifle, compared with the result. The process

is of course rapid in a plank, compared with a solid log. Fir deals take in their quantum within forty-eight hours—a beam of oak is not saturated under a month ; but what is a month, when we think of the years always considered necessary for the seasoning of timber in the usual process of drying ?

There remained io be answered certain important questions -to one of which we have already alluded. How long will the antiseptic virtue of this medicated timber abide in it? Will not the corrosive sublimate, essentially a poison, be disengaged from the vegetable body with which it has combined, under exposure to air and moisture ? And if this be the case, will not the wood lose its protection against the usual sources of dry rot, while, at the same time, the disengaged poison mingles with and contaminates the atmosphere breathed by the ship's crew ?

Mr. Faraday proceeded to detail a very ingenious series of chemical experiments, in which these startling doubts had led him to engage; and the issue of which, as far as they go, is satisfactory. Mr. Kyan stated that, on the contact of corrosive sublimate with any vegetable juice containing albumen, a new combination, a tertium quid, results; and upon this view Mr. Faraday experimented. He found that prepared canvas and calico, when washed in water until a certainty was obtained that that fluid would remove nothing more, still gave mercury to weak nitric acid ; the presence of a mercurial compound, proof against water, was thus, he thought, established—and he inferred that it could evolve, under ordinary circumstances of exposure, no noxious vapour whatever.

Enough has, we hope, been said to attract the notice of distant readers, to a subject which appears to be fixing every day more firmly the attention of the scientific circles in this metropolis. Whether the process of Mr. Kyan is as yet entitled to be sanctioned by the use of government in our public establishmentsand whether the example of Sir Robert Smirke, who has applied timber thus medicated in various new buildings under his charge, (in the Temple for instance,) will of itself be sufficient to stimulate the researches of his professional rivals, we do not pretend to say : but shall conclude with a very few observations on the benefits, national and domestic, which could not fail to result from the discovery and general adoption of a cheap, safe, and efficacious preventive of dry rot.

As to the Royal Navy, we need but refer to the long series of our preceding articles on this subject-especially to that in No. LIX.-for lamentable details of the extent and rapidity of the injuries sustained by the King's ships during the war, in consequence of this one cause. Owing principally to the prevalence of this disease, the average duration of ship-timber cannot be estimated

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at more than seven, or at most eight, years; and what may be the gross demand of the British fleet for timber? The Royal Navy consisted on the 1st of January, 1833, of 22 First-rates

of

108 to 120 guns 31 Second-rates

78 to 84 68 Third-rates

74 to 76 22 Fourth-rates

50 to 52 101 Fifth-rates

42 to 50 95 Sixth-rates

26 to 35 with seventy-four 18-gun vessels, and one hundred and sixty-one small craft, making in all 574 armed vessels. Mr. Edye estimates the quantity of wood required for the construction of a first-rate of 120 guns at 5880 loads—for an 80-gun ship, 4339 loads—for a 74, 3600—for a 52, 2372—for a fifth-rate, 1800 loads--and for a sixth-rate, 963. According to him, therefore, it would take, to build the existing 574 ships, not much under a million loads of timber;

and the quantity annually requisite to keep them seaworthy will be 125,000 loads. In what exact proportions this expense is occasioned by dry rot in seasoning, and by dry rot in ships, it is not in our power to say; but we are sure, whoever considers the detailed histories of individual vessels in our articles above referred to, in Mr. Knowles's book, and in the article · Dry Rot' in the Supplement to the Encyclopædia Britannica, will be prepared not to start when he hears that, according to the opinion of some of the best judges we know, the annual saving of timber in the Royal Navy, were a real cure for dry rot discovered and adopted, would not be much under 50,000 loads,

A single and simple fact, stated in three words, will perhaps bring the matter home to the reader's imagination, as readily as any given number of calculations and estimates. The Benbow was built in 1813; dry rot infected her; and she was repaired in 1818, at Portsmouth, without ever having been to sea, at the expense of 45,0001.

If the new or perfected invention, of which we have been treating, should answer even to the extent which Mr. Faraday said he considered to have been already placed beyond all doubt, it is obvious that the saving to the nation would be most important. Indeed, if it should come to no more than sparing us the expense of having all our ship timber felled many years before it is used, that, on so large a stock, would be no trivial saving. But we confess, when we think of five years in the fungus pit having left neither spot nor blemish on any one of nine specimens, we are inclined to consider this as a very subordinate feature of the case. In buildings on shore, more particularly large and public ones,

only only occasionally heated by fires, the effects of this timber-pest have of late been almost as destructive and costly as in the fleet and the dock-yard. The palace of Kew, à very recent structure, was obliged to be levelled to the ground solely from this cause : we believe we might say very nearly the same of the Royal Lodge in Windsor Park, demolished, all but a single room, immediately after the death of its founder King George IV.; and we fear there is truth in the prevalent report, that the malady has already manifested itself in the newly restored parts of Windsor Castle itself. In the churches lately erected in and about London, the damage caused in this way is known to be enormous; and we think Sir R. Smirke deserves much credit for taking the lead among his professional brethren in giving a full trial to an invention which, to say the least of it, appears to hold out a fair promise of striking at the roots of this great and growing mischief.

There are many persons who have examined into this affair, and formed expectations more extensive than we have as yet hinted at. According to them, the alburnum, which is at present chipped off all timbers before they are applied to the purposes of ship-building, on account of its being more liable to dry rot than the heartwood which it encircles, is thus liable only from its greater porosity and the consequent more ready exposure of its albumen to the action of heat and moisture ; but, if saturated with the solution of sublimate, will be just as secure against dry rot as heartwood, and available accordingly for a variety of naval purposes. They say the same as to larch and other woods, hitherto little used, in consequence chiefly of their porosity; and if they are right, (which in theory they seem to be,) the prospect held out to our planters, especially those in the north of Scotland, and we may add to the Canadian timber-trade, is certainly a most favourable one. The greater porosity of the American pine is, no doubt, the principal, if not the only source of its inferior estimation, as compared with that of the Baltic.

Mr. Faraday concluded his very interesting lecture on this subject, with some observations on the fears expressed by certain timber-merchants, that, if the new invention should be found to realize such expectations as these, the demand for their commodity would be much abridged. He answered, that if wood-work lasted longer than it does, it would be used much more extensively; that the demand for out-houses, sheds, and inclosures of all sorts would be prodigious; and that what most interested him in the whole affair was the prospect

of
great additional

and comfort being given to the domestic accommodations of the poorer classes. I am inclined,' he said, “to think, that the cottage will feel the benefit more than the palace.'

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ART.

ART. VII.-Illustrations of Political Economy. Nos. 1-12.

By Harriet Martineau. London, 1832—1893. HERE we have a monthly series of novels on Political Eco

nomy-Malthus, M'Culloch, Senior, and Mill, dramatised by a clever female hand. The authoress has, moreover, the high recommendation of being an Unitarian.* How could such a series fail to be considered as an important ally of the Society for the Diffusion of Useful Knowledge? What wonder that, from the Woolsack down to the Penny Cyclopædia, there should be a general chorus of exultation over the Sibylline leaves of Norwich ?

There is, we admit, much which it is impossible not to admire in Miss Martineau's productions—the praiseworthy intention and benevolent spirit in which they are written,--and the varied knowledge of nature and society, the acute discrimination of character, and remarkable power of entering into, and describing the feelings of the poorer classes, which several of her little narratives evince. But it is equally impossible not to laugh at the absurd trash which is seriously propounded by some of her characters, in dull didactic dialogues, introduced here and there in the most clumsy manner; and what is worst of all, it is quite impossible not to be shocked, nay disgusted, with many of the unféminine and mischievous doctrines on the principles of social welfare, of which these tales are made the vehicle.

This young lady's work consists of the several chapters of the Principles of Political Economy,' according to the doctors we have named, rendered into popular stories. Each tale has attached to it the principle it is intended to illustrate ; and the readers of each little volume are expected, we suppose, by the time they arrive at the end, to have duly imbibed and digested the substance of these principles. We can only say, if any individual has accomplished this feat, his powers of deglutition and digestion are such as an ostrich might envy. Hear, however, how complacently the fair writer talks of her own doings in her preface :

• We do not dedicate our series to any particular class of society, because we are sure that all classes bear an equal relation to the science, and we much fear that it is as little familiar to the bulk of one as of another. We should not be so ready to suspect this ignorance, if we did not hear so much of the difficulty of the subject. We trust it will be found that as the leading principles come out in order, one after another, they are so clear, so indisputable, so apparently familiar, that the wonder is when the difficulty is to come,'— p. 13. Miss Martineau has no modest misgivings:

* Her theological works are all, we believe, published at the expense of “The Unitarian Association.' Such, at least, is the case with her •Essential Principles of Christianity,' addressed to her dear Roman Catholic brethren.' London. 1831.

. She

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